#include <stdio.h>

int fib(int n)
{
    int a = 1;
    int b = 1;
    int c = 1;
    while(n>=3){
        c = a + b;
        a = b;
        b = c;
        n--;
    }

    return c;
}

int main(int argc, char const *argv[])
{
    printf("%d", fib(5));
    return 0;
}
